<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            margin: 0;
            background-color: #f00;
        }
        .box {
            width: 500px;
            height: 100px;
            text-align: center;
            line-height: 100px;
            font-size: 50px;
            background-image: linear-gradient(to right, transparent, #00eeff, transparent);
        }
    </style>
</head>
<body>
    <div class="box">hello world!</div>
</body>
</html>